Gland packing

ABSTRACT

A gland packing which is made of a material configured by windingly laminating an expanded graphite tape into a spiral shape. In the gland packing, ring-like projected parts are disposed on end faces of a die mold packing part made of an expanded graphite tape windingly laminated into a spiral shape so as to be integrated with the part. Ring-like seal members are brought into tight contact with the end faces of the die mold packing part excluding the ring-like projected parts in such a manner that the ring-like projected parts are projected in an axial direction beyond the outer faces of the respective ring-like seal members.

TECHNICAL FIELD

The present invention relates to a gland packing which is useful as ashaft seal device for a hydraulic machine such as a valve or a pump, andmore particularly to a gland packing which is charged into a stuffingbox and pressed by a packing gland in an axial direction so as to bebrought into tight contact with the outer peripheral face of a shaft ora valve rod, thereby forming a shaft seal part.

BACKGROUND ART

As such a gland packing, conventionally, known is a die mold packing 51having a usual structure shown in FIG. 25. The die mold packing 51 isconfigured by windingly laminating a tape-like material 50 such as anexpanded graphite tape into a spiral shape, and then die-molding thelamination into a ring-like shape. Such a die mold packing 51 is used inthe following manner. As shown in FIG. 26, in a stuffing box 54, the diemold packings 51, and a plurality of laminate packings 53 which areobtained by laminating ring-like sheet materials 52 havingimpermeability are alternately disposed on the outer periphery of ashaft or a valve rod 55 (hereinafter, referred to as “valve rod or thelike”) in an axial direction. Alternatively, as shown in FIG. 27, thedie mold packings 51, and braided packings 56 which are well known inthe art are combinedly disposed. These packings are pressed in the axialdirection through a packing gland 57 so that their inner peripheral faceparts are brought into tight contact with the outer peripheral face ofthe valve rod or the like 55, thereby performing the shaft sealingoperation.

Furthermore, also a gland packing 58 is known in which, as shown in FIG.28, a ring-like projected part 51 a is formed on an end face in an axialdirection of the die mold packing 51 and in an outer end portion in aradial direction so that the ring-like projected part is projectedoutward in the axial direction, and a ring-like recess 56 a which isformed on an end face in the axial direction of the braided packings 56and in an outer end portion in a radial direction is fitted onto thering-like projected part 51 a, thereby integrating the packings 51 and56 into one body. Also the integrated gland packing 58 is used in thefollowing manner. As shown in FIG. 29, the integrated gland packings 58are combinedly disposed in the stuffing box 54 together with the diemold packings 51 having the ring-like projected part 51 a. In the samemanner as described above, these packings are pressed in an axialdirection through the packing gland 57 so that their inner peripheralface, parts are brought into tight contact with the outer peripheralface of the valve rod or the like 55, thereby performing the shaftsealing operation.

In a prior art gland packing mainly consisting of the die mold packings51, as shown in FIGS. 25 and 28, minute gaps 59 are inevitably formed inwindingly laminated parts of the tape-like material 50. A pressurizedfluid penetrates into the minute gaps 59, and leakage indicated by thearrow a easily occurs. Particularly when a gas fluid of low molecularweight flows through the hydraulic machine, it is very difficult toprevent penetration leakage from occurring.

Furthermore, the die mold packing 51 which is configured by windinglylaminating the tape-like material 50 has originally a lower strength. Ina use manner, the die mold packing is disposed in substantially parallelto the axis of the valve rod or the like 55. When the material ispressed in an axial direction, the material is swollen out to enter thegaps so that stress relaxation easily occurs. Furthermore, the processof the die molding is conducted at a high face pressure. When the diemold has a rectangular section shape, therefore, the die mold cannotexhibit sufficient sealing performance at a low tightening force.

Moreover, when the die mold packings 51 and the laminate packings 53 arecombinedly used as shown in FIG. 26, the amount of deformation of thelaminate packings 53 in the pressurizing process is small, and hence thelaminate packings 53 must be produced with very high dimensionalaccuracy. Furthermore, the parts of the laminate packings 53 are easilyworn. Even when the parts are worn at a very small amount, the contactsurface pressure acting on the valve rod or the like 55 is extremelylowered, thereby producing a problem in that sealing performance islargely impaired.

The invention has been conducted in view of the above-mentionedcircumstances. It is an object of the invention to provide a glandpacking which can prevent penetration leakage from occurring, which canbe sufficiently deformed so as to exhibit sure sealing properties evenat a low tightening force, and which has following properties against asmall amount of wear so as to ensure high sealing performance for a longterm.

DISCLOSURE OF THE INVENTION

In order to attain the object, in the gland packing of the invention, aring-like projected part which is projected outward in an axialdirection is formed on at least one end face in an axial direction of adie mold packing part and in at least one of outer and inner endportions in a radial direction, the die mold packing part beingconfigured by windingly laminating an expanded graphite tape into aspiral shape and die-molding the lamination into a ring-like shape, aring-like seal member is brought into tight contact with the one endface in the axial direction of the die mold packing part excluding thering-like projected part, and the ring-like projected part is projectedin the axial direction beyond an outer face of the ring-like sealmember.

Alternatively, the gland packing may be configured in the followingmanner. The ring-like projected part is projected outward in the axialdirection from the both end faces in the axial direction of the die moldpacking part and in the outer or inner end portion in a radialdirection, or a ring-like projected part is projected from one end facein the axial direction of the die mold packing part and in the inner endportion in a radial direction, and also from the other end face in theaxial direction of the die mold packing part and in the outer endportion in a radial direction so that the ring-like projected parts areprojected outward in the axial direction. Ring-like seal members arerespectively brought into tight contact with the end faces in the axialdirection of the die mold packing part excluding the ring-like projectedparts.

In the thus configured invention, a ring-like seal member is broughtinto tight contact with at least one of the end faces in the axialdirection of the die mold packing part. Even when a pressurized fluidpenetrates into minute gaps formed in windingly laminated parts of theexpanded graphite tape constituting the die mold packing part,therefore, the leakage of the fluid is blocked by the ring-like sealmember and stress relaxation due to the swelling out in the axialdirection of the die mold packing part is suppressed by the ring-likeseal member. The ring-like projected part which is projected outward inthe axial direction is formed in the die mold packing part. When thegland packing is to be used while being charged in a stuffing box,therefore, the projected part is easily deformed only by applying a lowtightening force in the axial direction, and hence the density of theprojected part is increased and a large stress is generated in a radialdirection of the projected part so that the packing is strongly broughtinto tight contact with the inner face of the stuffing box and the outerperipheral face of a valve rod or the like. This surely preventspenetration leakage from the projected part from occurring, and enhancessealing properties between the stuffing box and the valve rod.Furthermore, the ring-like projected part has a closely packed foldedstructure and is very elastic, and hence the ring-like projected partcan satisfactorily follow a small amount of wear, thereby ensuringpenetration leak prevention and high sealing properties.

In the other gland packing of the invention, a ring-like projected partwhich is projected outward in an axial direction is formed on at leastone end face in the axial direction of a die mold packing part and in atleast one of outer and inner end portions in a radial direction, the diemold packing part being configured by windingly laminating an expandedgraphite tape into a spiral shape and die-molding the lamination into aring-like shape, a ring-like seal member is brought into tight contactwith the one end face in the axial direction of the die mold packingpart excluding the ring-like projected part, the outer face of thering-like seal member is formed as an oblique circular cone face whichis positioned more outward in the axial direction as moving toward thering-like projected part, and the projection end face of the ring-likeprojected part is substantially positioned in an extension plane of theoblique circular cone face.

The gland packing may be configured so that ring-like projected partsare respectively outward projected in the axial direction from the bothend faces in the axial direction of the die mold packing part and in theouter or inner end portion in a radial direction, or ring-like sealmembers are respectively brought into tight contact with the end facesin the axial direction of the die mold packing part excluding thering-like projected parts.

In the thus configured gland packing, even when a pressurized fluidpenetrates into minute gaps formed in windingly laminated parts of theexpanded graphite tape constituting the die mold packing part, theleakage of the fluid is blocked by the ring-like seal member and stressrelaxation due to the swelling out in the axial direction of the diemold packing part is suppressed by the ring-like seal member. Thering-like projected part which is projected outward in the axialdirection is formed in the die mold packing part, and the projection endface of the ring-like projected part and the outer face of the ring-likeseal member are formed as an oblique circular cone face which ispositioned more outward in the axial direction as moving toward thering-like projected part. When the gland packing is to be used whilebeing charged in a stuffing box, therefore, the projected part and thering-like seal member are easily deformed only by applying a lowtightening force in the axial direction, so that the projected part andthe ring-like seal member are positioned in a plane substantiallyperpendicular to the axis of the valve rod or the like, and hence thedensity of the projected part is increased and a large stress isgenerated in a radial direction so that the packing is strongly broughtinto tight contact with the inner face of the stuffing box and the outerperipheral face of a valve rod or the like. This can surely preventpenetration leakage through the projected part from occurring, andenhance sealing properties between the stuffing box and the valve rod.Furthermore, the ring-like projected part has a closely packed foldedstructure and is very elastic, and hence the ring-like projected partcan satisfactorily follow a small amount of wear, thereby ensuringpenetration leak prevention and high sealing properties.

In the further gland packing of the invention, a ring-like projectedpart which is projected outward in the axial direction is formed on atleast one end face in an axial direction of a die mold packing part andin at least one of outer and inner end portions in a radial direction,the die mold packing part being configured by windingly laminating anexpanded graphite tape into a spiral shape and die-molding thelamination into a ring-like shape, a ring-like seal member is broughtinto tight contact with the one end face in the axial direction of thedie mold packing part excluding the ring-like projected part, the outerface of the ring-like seal member is formed as an oblique circular coneface which is positioned more inward in the axial direction as movingtoward the ring-like projected part, and the projection end face of thering-like projected part is substantially positioned in an extensionplane of the oblique circular cone face.

The gland packing may be configured so that ring-like projected partsare respectively outward projected in the axial direction from the bothend faces in the axial direction of the die mold packing part and in theouter or inner end portion, or ring-like seal members are respectivelybrought into tight contact with the end faces in the axial direction ofthe die mold packing part excluding the ring-like projected parts.

The gland packing is different from the above-mentioned other glandpackings only in that the oblique circular cone face constituted by theprojection end face of the ring-like projected part and the outer faceof the ring-like seal member is formed as a circular cone face of aninverse inclination so that the oblique circular cone face is positionedmore inward in the axial direction as moving toward the projected part.According to the gland packing, sure prevention of the penetrationleakage and high sealing properties can be exerted by the synergisticeffect of the following configurations: the leakage of a pressurizedfluid which penetrates into minute gaps formed in windingly laminatedparts of the expanded graphite tape constituting the die mold packingpart is prevented from occurring by the ring-like seal member; stressrelaxation due to the swelling out in the axial direction of the diemold packing part is suppressed by the ring-like seal member; and, whenthe gland packing is to be used while being charged in a stuffing box,the projected part and the ring-like seal member are easily deformedonly by applying a low tightening force in the axial direction, so thatthe projected part and the ring-like seal member are positioned in aplane substantially perpendicular to the axis of the valve rod or thelike, and hence the density of the projected part is increased and alarge stress is generated in a radial direction so that the packing isstrongly brought into tight contact with the inner face of the stuffingbox and the outer peripheral face of the valve rod or the like, wherebypenetration leakage through the projected part is surely prevented fromoccurring and sealing properties between the stuffing box and the valverod are enhanced.

As the ring-like seal member in the gland packing of each of theabove-mentioned configurations, any one of a lamination of a sheetmaterial having impermeability, a single plate, and metal foil may beselectively used.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a longitudinal section view of a gland packing of a firstembodiment of the invention.

FIG. 2 is a longitudinal section view of a gland packing of a secondembodiment of the invention.

FIG. 3 is a longitudinal section view of a gland packing of a thirdembodiment of the invention.

FIG. 4 is a longitudinal section view of a gland packing of a fourthembodiment of the invention.

FIG. 5 is a longitudinal section view of a gland packing of a fifthembodiment of the invention.

FIG. 6 is a longitudinal section view of a gland packing of a sixthembodiment of the invention.

FIG. 7 is a longitudinal section view of a gland packing of a seventhembodiment of the invention.

FIG. 8 is a longitudinal section view of a gland packing of an eighthembodiment of the invention.

FIG. 9 is a longitudinal section view of a gland packing of a ninthembodiment of the invention.

FIG. 10 is a longitudinal section view of a gland packing of an eleventhembodiment of the invention.

FIG. 11 is a longitudinal section view of a gland packing of a twelfthembodiment of the invention.

FIG. 12 is a longitudinal section view of a gland packing of athirteenth embodiment of the invention.

FIG. 13 is a longitudinal section view of a gland packing of afourteenth embodiment of the invention.

FIG. 14 is a longitudinal section view of a gland packing of a fifteenthembodiment of the invention.

FIG. 15 is a longitudinal section view of a gland packing of a sixteenthembodiment of the invention.

FIG. 16 is a longitudinal section view of a gland packing of aseventeenth embodiment of the invention.

FIG. 17 is a longitudinal section view of a gland packing of aneighteenth embodiment of the invention.

FIG. 18 is a longitudinal section view showing use example 1 of thegland packings of the embodiments of the invention.

FIG. 19 is a longitudinal section view showing use example 2 of thegland packings of the embodiments of the invention.

FIG. 20 is a longitudinal section view showing use examples 3 to 5 ofthe gland packings of the embodiments of the invention.

FIG. 21 is an enlarged half longitudinal section view illustrating thepenetration leakage prevention action in a use state of the glandpacking of the second embodiment of the invention.

FIG. 22 is an enlarged half longitudinal section view illustrating thedeformation action of a projected part in a use state of the glandpacking of the first embodiment of the invention.

FIG. 23 is a table in which stress generating states of the packings ofthe invention, a prior art packing, and comparison packings are listed.

FIG. 24 is a table showing results of gas-seal tests of use examples 1to 5 of the gland packing of the invention, and use examples of priorart packings.

FIG. 25 is a half longitudinal section view showing an example of aprior art gland packing.

FIG. 26 is a longitudinal section view showing a use example of theprior art gland packing.

FIG. 27 is a longitudinal section view showing another use example ofthe prior art gland packing.

FIG. 28 is a half longitudinal section view showing another example of aprior art gland packing.

FIG. 29 is a longitudinal section view showing a use example of thegland packing of FIG. 28.

FIG. 30 is a half longitudinal section view showing an example of agland packing which is a comparison example.

FIG. 31 is a half longitudinal section view showing another example of agland packing which is a comparison example.

BEST MODES FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the invention will be described withreference to the drawings.

First Embodiment

FIG. 1 is a longitudinal section view of a gland packing G1 of a firstembodiment of the invention. In the figure, 1 designates a die moldpacking part. The die mold packing part 1 is configured by windinglylaminating ah expanded graphite tape 1 a into a spiral shape, anddie-molding the lamination into a ring-like shape having dimensions ofan inner diameter d of 32 mm, an outer diameter D of 48 mm, and a heighth of 12 mm. 2 designates a ring-like projected part which is projectedoutward in an axial direction from one end face in the axial directionof the die mold packing part 1 and in the outer end portion in a radialdirection (projection amount δ1=2 mm) and integrally formed, and 3designates a ring-like projected part which is projected outward in anaxial direction (opposite to the ring-like projected part 2) from theother end face in the axial direction of the die mold packing part 1 andin the inner end portion in a radial direction (projection amount δ2=2mm) and integrally formed. 4 and 5 designate ring-like seal memberswhich are respectively brought into tight contact, with the end faces inthe axial direction of the die mold packing part 1 excluding the outerand inner ring-like projected parts 2 and 3. The ring-like seal members4 and 5 are formed by laminating three punched products of an expandedgraphite sheet (thickness of 0.38 mm) having impermeability, and thelaminated product is compressed together with the die mold packing part1. As a result, the section shape shown in FIG. 1 is formed. As theexpanded graphite tape 1 a constituting the die mold packing part 1, aproduct obtained by compounding (laminating) knitted meshes of a thinmetal wire, or metal foil may be used. The ring-like seal members 4 and5 may adhere to the die mold packing part 1 so as to be integratedtherewith. However, the adhesion of the members is not necessary becausethe positioning of the members is conducted by the existence of theprojected parts 2 and 3.

Second Embodiment

FIG. 2 is a longitudinal section view of a gland packing G2 of a secondembodiment of the invention. In the embodiment, a ring-like projectedpart 2 is projected outward in an axial direction from one end face inthe axial direction of a die mold packing part 1 and in the outer endportion in a radial direction, so as to be integrally formed, and aring-like seal member 4 is brought into tight contact with only one endface in the axial direction of the die mold packing part 1 excluding thering-like projected part 2. The method of forming the section shapeshown in the figure, the configuration of the die mold packing part 1and the ring-like seal member 4, the dimensions (d, D, h, δ1) of theparts, etc. are the same as those of the first embodiment, and hencetheir detailed description is omitted.

Third Embodiment

FIG. 3 is a longitudinal section view of a gland packing G3 of a thirdembodiment of the invention. In the embodiment, ring-like projectedparts 2A and 2B are projected outward in an axial direction from theboth end faces in the axial direction of a die mold packing part 1 andin the outer end portion in a radial direction, so as to be integrallyformed, and ring-like seal members 4 and 5 are respectively brought intotight contact with the both end faces in the axial direction of the diemold packing part 1 excluding the ring-like projected parts 2A and 2B.The method of forming the section shape shown in the figure, theconfiguration of the die mold packing part 1 and the ring-like sealmembers 4 and 5, the dimensions (d, D, h, δ1, δ2) of the parts, etc. arethe same as those of the first embodiment, and hence their detaileddescription is omitted.

Fourth Embodiment

FIG. 4 is a longitudinal section view of a gland packing G4 of a fourthembodiment of the invention. In the embodiment, a ring-like projectedpart 3 is projected outward in an axial direction from one end face inthe axial direction of the die mold packing part 1 and in the inner endportion in a radial direction, so as to be integrally formed, and aring-like seal member 4 is brought into tight contact with only one endface in the axial direction of the die mold packing part 1 excluding thering-like projected part 3. The method of forming the section shapeshown in the figure, the configuration of the die mold packing part 1and the ring-like seal member 4, the dimensions (d, D, h, δ1) of theparts, etc. are the same as those of the first embodiment, and hencetheir detailed description is omitted.

Fifth Embodiment

FIG. 5 is a longitudinal section view of a gland packing G5 of a fifthembodiment of the invention. In the embodiment, ring-like projectedparts 3A and 3B are projected outward in an axial direction from theboth end faces in the axial direction of a die mold packing part 1 andin the inner end portion in a radial direction, so as to be integrallyformed, and ring-like seal members 4 and 5 are respectively brought intotight contact with the both end faces in the axial direction of the diemold packing part 1 excluding the ring-like projected parts 3A and 3B.The method of forming the section shape shown in the figure, theconfiguration of the die mold packing part 1, the dimensions (d, D, h,δ1, δ2) of the parts, etc. are the same as those of the first embodimentexcept that punched stainless steel plates of a thickness of 0.2 mm areused as the ring-like seal members 4 and 5, and hence their detaileddescription is omitted.

Sixth Embodiment

FIG. 6 is a longitudinal section view of a gland packing G6 of a sixthembodiment of the invention. In the figure, 1 designates a die moldpacking part. The die mold packing part 1 is configured by windinglylaminating an expanded graphite tape 1 a into a spiral shape, anddie-molding the lamination into a ring-like shape having dimensions ofan inner diameter d of 32 mm, an outer diameter D of 48 mm, and a heighth of 10 mm. 6 designates a ring-like projected part which is projectedoutward in an axial direction from one end face in the axial directionof the die mold packing part 1 and in the outer end portion in a radialdirection (projection amount δ1=0.2 mm) and integrally formed, and 7designates a ring-like projected part which is projected outward in anaxial direction (opposite to the ring-like projected part 6) from theother end face in the axial direction of the die mold packing part 1 andin the inner end portion in a radial direction (projection amount δ2=0.2mm) and integrally formed. 8 and 9 designate ring-like seal memberswhich are respectively brought into tight contact with the end faces inthe axial direction of the die mold packing part 1 excluding the outerand inner ring-like projected parts 6 and 7. The ring-like seal members8 and 9 are configured by punched stainless steel plates of a thicknessof 0.2 mm so that outer faces 8 a and 9 a of the members arerespectively formed as oblique circular cone faces which have aninclination θ of 15° to a plane perpendicular to the axis so as to bepositioned more outward in the axial direction as moving toward thering-like projected parts 6 and 7, and the projection end faces 6 a and7 a of the ring-like projected parts 6 and 7 are respectivelysubstantially positioned in extension planes of the oblique circularcone faces 8 a and 9 a.

Seventh Embodiment

FIG. 7 is a longitudinal section view of a gland packing G7 of a seventhembodiment of the invention. In the embodiment, a ring-like projectedpart 6 is projected outward in an axial direction from one end face inthe axial direction of a die mold packing part 1 and in the outer endportion in a radial direction, so as to be integrally formed, and aring-like seal member 8 is brought into tight contact with only one endface in the axial direction of the die mold packing part 1 excluding thering-like projected part 6. The outer face 8 a of the ring-like sealmember 8 is formed as an oblique circular cone face which is positionedmore outward in an axial direction as moving toward the ring-likeprojected part 6. The ring-like seal member 8 is formed by laminatingthree punched products of an expanded graphite sheet (thickness of 0.38mm) having impermeability, and the laminated product is compressedtogether with the die mold packing part 1. As a result, the sectionshape shown in FIG. 7 is formed. The configuration of the die moldpacking part 1 other than the above, the dimensions (d, D, h, δ1, θ ofthe parts, etc. are the same as those of the sixth embodiment, and hencetheir detailed description is omitted.

Eighth Embodiment

FIG. 8 is a longitudinal section view of a gland packing G8 of an eighthembodiment of the invention. In the embodiment, ring-like projectedparts 6A and 6B are projected outward in an axial direction from theboth end faces in the axial direction of a die mold packing part 1 andin the outer end portion in a radial direction, so as to be integrallyformed, and ring-like seal members 8 and 9 are respectively brought intotight contact with the both end faces in the axial direction of the diemold packing part 1 excluding the ring-like projected parts 6A and 6B.Outer faces 8 a and 9 a of the ring-like seal members 8 and 9 arerespectively formed as oblique circular cone faces which are positionedmore outward in an axial direction as moving toward the ring-likeprojected parts 6A and 6B. The ring-like seal members 8 and 9 areconfigured by using a punched polytetrafluoroetylene (PTFE) resin sheetof a thickness of 1.0 mm, and the sheet is compressed together with thedie mold packing part 1. As a result, the section shape shown in FIG. 8is formed. The configuration of the die mold packing part 1 other thanthe above, the dimensions (d, D, h, δ1, δ2, θ of the parts, etc. are thesame as those of the sixth embodiment, and hence their detaileddescription is omitted.

Ninth Embodiment

FIG. 9 is a longitudinal section view of a gland packing G9 of a ninthembodiment of the invention. In the embodiment, a ring-like projectedpart 7 is projected outward in an axial direction from one end face inthe axial direction of a die mold packing part 1 and in the inner endportion in a radial direction, so as to be integrally formed, and aring-like seal member 8 is brought into tight contact with only one endface in the axial direction of the die mold packing part 1 excluding thering-like projected part 7. The outer face 8 a of the ring-like sealmember 8 is formed as an oblique circular cone face which is positionedmore outward in an axial direction as moving toward the ring-likeprojected part 7. The ring-like seal member 8 is formed by laminatingthree punched products of an expanded graphite sheet (thickness of 0.38mm) having impermeability, and the laminated product is compressedtogether with the die mold packing part 1. As a result, the sectionshape shown in FIG. 7 is formed. The configuration of the die moldpacking part 1 other the above, the dimensions (d, D, h, δ1, θ of theparts, etc. are the same as those of the sixth embodiment, and hencetheir detailed description is omitted.

Tenth Embodiment

A gland packing G10 (see FIG. 9) of a tenth embodiment is strictly thesame as the ninth embodiment except that PTFE-impregnated glass fiberfabric is used as the ring-like seal member 8, and hence itsillustration and detailed description are omitted.

Eleventh Embodiment

FIG. 10 is a longitudinal section view of a gland packing G11 of aneleventh embodiment of the invention. In the embodiment, among aring-like projected part 6 which is projected outward in an axialdirection from one end face in the axial direction of a die mold packingpart 1 and in the outer end portion in a radial direction and integrallyformed, and a ring-like projected part 7 which is projected outward inan axial direction (opposite to the ring-like projected part 6) from theother end face in the axial direction of the die mold packing part 1 andin the inner end portion in a radial direction and integrally formed,the projection end face 6 a of the ring-like projected part 6 which isoutside in a radial direction is projected outward in the axialdirection beyond an oblique circular cone face 8 a of one seal member 8of ring-like seal members 8 and 9 which are brought into tight contactwith the both end faces in the axial direction of the die mold packingpart 1 so as to be formed as oblique circular cone faces which have aninclination θ of 15° to a plane perpendicular to the axis. The method offorming the section shape shown in the figure, the other configuration,the dimensions of the parts, etc. are the same as those of the sixthembodiment, and hence their detailed description is omitted.

Twelfth Embodiment

FIG. 11 is a longitudinal section view of a gland packing G12 of atwelfth embodiment of the invention. In the embodiment, the projectionend face 6 a of a ring-like projected part 6 which is projected outwardin an axial direction from one end face in the axial direction of a diemold packing part 1 and in the outer end portion in a radial directionis projected outward in the axial direction beyond an oblique circularcone face 8 a of a ring-like seal member 8 which is brought into tightcontact on the side of the one end face in the axial direction of thedie mold packing part 1 so that the outer face 8 a is formed as anoblique circular cone face which is positioned more outward in an axialdirection as moving toward the ring-like projected part 6. The method offorming the section shape shown in the figure, the other configuration,the dimensions of the parts, etc. are the same as those of the seventhembodiment, and hence their detailed description is omitted.

Thirteenth Embodiment

FIG. 12 is a longitudinal section view of a gland packing G13 of athirteenth embodiment of the invention. In the embodiment, theprojection end faces 6 a and 6 b of ring-like projected parts 6A and 6Bwhich are respectively projected outward in an axial direction from theboth end faces in the axial direction of a die mold packing part 1 andin the outer end portions in a radial direction are projected outward inan axial direction beyond oblique circular cone faces 8 a and 9 a of thering-like seal members 8 and 9 which are brought into tight contact withthe both end faces in the axial direction of the die mold packing part 1so that the outer faces 8 a and 9 a are formed as oblique circular conefaces which are respectively positioned more outward in an axialdirection as moving toward the ring-like projected parts 6A and 6B. Themethod of forming the section shape shown in the figure, the otherconfiguration, the dimensions of the parts, etc. are the same as thoseof the eighth embodiment, and hence their detailed description isomitted.

Fourteenth Embodiment

FIG. 13 is a longitudinal section view of a gland packing G14 of afourteenth embodiment of the invention. In the embodiment, theprojection end face 7 a of the ring-like projected part 7 which isprojected outward in an axial direction from one end face in the axialdirection of a die mold packing part 1 and in the inner end portion in aradial direction is projected outward in the axial direction beyond anoblique circular cone face 8 a which is brought into tight contact onthe side of the one end face in the axial direction of the die moldpacking part 1 so that the outer face 8 a is formed as an obliquecircular cone face which is positioned more outward in an axialdirection as moving toward the ring-like projected part 7. The method offorming the section shape shown in the figure, the other configuration,the dimensions of the parts, etc. are the same as those of the ninthembodiment, and hence their detailed description is omitted.

Fifteenth Embodiment

FIG. 14 is a longitudinal section view of a gland packing G15 of afifteenth embodiment of the invention. The embodiment is configured sothat the outer faces 8 a and 9 a of the ring-like projected parts 8 and9 which are respectively brought into tight contact with the both endfaces in the axial direction of a die mold packing part 1 arerespectively formed as oblique circular cone faces which have aninclination θ of 15° to a plane perpendicular to the axis so as to bepositioned more inward in an axial direction as moving toward thering-like projected parts 6 and 7, in the opposite manner as the sixthembodiment, and the projection end faces 6 a and 7 a of the ring-likeprojected parts 6 and 7 are respectively substantially positioned inextension planes of the oblique circular cone faces 8 a and 9 a. Themethod of forming the section shape shown in the figure, the otherconfiguration, the dimensions of the parts, etc. are the same as thoseof the sixth embodiment, and hence their detailed description isomitted.

Sixteenth Embodiment

FIG. 15 is a longitudinal section view of a gland packing G16 of asixteenth embodiment of the invention. In the embodiment, a ring-likeseal member 8 which is brought into tight contact only on the side ofone end face in an axial direction of a die mold packing part 1 isformed so that the outer face 8 a is formed as an oblique circular coneface which is positioned more inward in an axial direction as movingtoward a ring-like projected part 6 in the opposite manner as theseventh embodiment. The method of forming the section shape shown in thefigure, the other configuration, the dimensions of the parts, etc. arethe same as those of the seventh embodiment, and hence their detaileddescription is omitted.

Seventeenth Embodiment

FIG. 16 is a longitudinal section view of a gland packing G17 of aseventeenth embodiment of the invention. In the embodiment, ring-likeseal members 8 and 9 which are respectively brought into tight contactwith the both end faces in an axial direction of a die mold packing part1 are formed so that the outer faces 8 a and 9 a are formed as obliquecircular cone faces which are positioned more inward in an axialdirection as moving toward ring-like projected parts 6A and 6B in theopposite manner as the eighth embodiment. The method of forming thesection shape shown in the figure, the other configuration, thedimensions of the parts, etc. are the same as those of the eighthembodiment, and hence their detailed description is omitted.

Eighteenth Embodiment

FIG. 17 is a longitudinal section view of a gland packing G18 of aneighteenth embodiment of the invention. In the embodiment, a ring-likeseal member 8 which is brought into tight contact only on the side ofone end face in an axial direction of a die mold packing part 1 isformed so that the outer face 8 a is formed as an oblique circular coneface which is positioned more inward in an axial direction as movingtoward a ring-like projected part 6 in the opposite manner as the ninthembodiment. The method of forming the section shape shown in the figure,the other configuration, the dimensions of the parts, etc. are the sameas those of the ninth embodiment, and hence their detailed descriptionis omitted.

In the gland packings G1 to G18 of the embodiments, as the expandedgraphite tape 1 a constituting the die mold packing part 1, a productobtained by compounding (laminating) knitted meshes of a thin metalwire, or metal foil may be used. As the ring-like seal members 4, 5, 8,and 9, any sheet having impermeability may be used. In accordance withvarious use conditions, for example, the material of the members may beadequately selected from an expanded graphite sheet; a stainless steelplate; and a PTFE sheet; and in addition a film of polyphenylene sulfide(PPS), polyether ether ketone (PEEK), aramid, or the like; a sheet ofnitrile-butadiene rubber (NBR), chloroprene rubber (CR), syntheticrubber (SR), fluoro rubber, or the like; and a metal foil or a thinplate of copper, aluminum, lead, inconel, or the like.

The ring-like seal members 4, 5, 8, and 9 may adhere to the die moldpacking part 1 so as to be integrated therewith. However, the adhesionof the members is not necessary because the positioning of the membersis conducted by the existence of the projected parts 2, 3, 6, and 7.

Typical use manners of the gland packings of the thus configuredembodiments will be described.

USE EXAMPLE 1

FIG. 18 shows a use manner in which a plurality of gland packings G2 ofthe second embodiment and gland packings G4 of the fourth embodiment arealternately arranged in an axial direction on the outer peripheral faceof a valve rod or the like 11 in a stuffing box 10, braided packings 12and 12 are respectively disposed at the both ends in the axial directionof the arrangement, and a tightening force is applied to one end in theaxial direction through a packing gland 13, thereby forming a shaft sealpart. In the use manner, minute gaps 14 such as shown in FIG. 21 areformed in windingly laminated parts of the expanded graphite tape 1 aconstituting the die mold packing part 1 of each of the gland packingsG2 and G4, and a pressurized fluid penetrates into the minute gaps 14.However, the leakage of the penetrating fluid to the outside is blockedby the ring-like seal member 4 and also stress relaxation due to theswelling out in the axial direction of the die mold packing part 1 issuppressed by the ring-like seal member 4. The ring-like projected part2 which is projected outward in the axial direction from the die moldpacking part 1 is easily deformed by applying a low tightening force inthe axial direction, and hence the density of the projected part isincreased and a large stress is generated in a radial direction so thatthe packing is strongly brought into tight contact with the inner faceof the stuffing box 10 and the outer peripheral face of the valve rod orthe like 11. This surely prevents also the leakage through the projectedpart 2 from occurring, and enhances sealing properties between thestuffing box 10 and the valve rod or the like 11. Furthermore, thering-like projected part 2 has a closely packed folded structure and isvery elastic, and hence can satisfactorily follow a small amount ofwear, thereby ensuring penetration leak prevention and high sealingproperties.

USE EXAMPLE 2

FIG. 19 shows a use manner in which a plurality of gland packings G1 ofthe first embodiment and gland packings 51 of the prior art shown inFIG. 25 are alternately arranged in an axial direction on the outerperipheral face of a valve rod or the like 11 in a stuffing box 10, anda tightening force is applied to one end in the axial direction througha packing gland 13, thereby forming a shaft seal part. In the usemanner, even when a pressurized fluid penetrates into the minute gaps 59such as shown in FIG. 25 formed in windingly laminated parts of thetape-like material 50 constituting the die mold packing part 51, theleakage of the penetrating fluid to the outside is blocked by thering-like seal members 4 and 5 of the gland packing G1 and also stressrelaxation due to the swelling out in the axial direction of the diemold packing part 1 is suppressed by the ring-like seal members 4 and 5.The ring-like projected parts 2 and 3 which are projected outward in theaxial direction from the die mold packing part lure easily deformed asshown in FIG. 22 by applying a low tightening force in the axialdirection, and hence the density of the projected part is increased anda large stress is generated in a radial direction so that the packing isstrongly brought into tight contact with the inner face of the stuffingbox 10 and the outer peripheral face of the valve rod or the like 11. Inthe same manner as use example 1 described above, this surely preventsalso the leakage through the projected parts 2 and 3 from occurring, andenhances sealing properties between the stuffing box 10 and the valverod or the like 11. Furthermore, the ring-like projected parts 2 and 3have a closely packed folded structure and are very elastic, and hencecan satisfactorily follow a small amount of wear, thereby ensuringpenetration leak prevention and high sealing properties.

USE EXAMPLE 3

FIG. 20 shows a use manner in which a plurality of gland packings G7 ofembodiment 7 and gland packings G9 or G10 of embodiment 9 or 10 arealternately arranged in an axial direction on the outer peripheral faceof a valve rod or the like 11 in a stuffing box 10, and a tighteningforce is applied to one end in the axial direction through a packinggland 13, thereby forming a shaft seal part. In the use manner, in thesame manner as the use examples described above, the ring-like sealmember 8 blocks the leakage of the fluid penetrating into the minutegaps 14 to the outside, and suppresses stress relaxation due to theswelling out in the axial direction of the die mold packing part 1.Furthermore, the ring-like projected parts 6A and 6B and the ring-likeseal member 8 are easily deformed by applying a low tightening force inthe axial direction so as to be positioned in a plane substantiallyperpendicular to the axis of the valve rod or the like 11, and hence thedensity of the projected parts 6A and 6B is increased and a large stressis generated in a radial direction so that the projected parts arestrongly brought into tight contact with the inner face of the stuffingbox 10 and the outer peripheral face of the valve rod or the like 11.This can surely prevent penetration leakage through the projected parts6A and 6B from occurring, and maintain sealing properties between thestuffing box 10 and the valve rod or the like 11 at a high level.

USE EXAMPLE 4

In place of the gland packings G7 and G9 or G10 used in use example 3shown in FIG. 20, the gland packing G12 of embodiment 12 and the glandpacking G14 of embodiment 14 are similarly used so as to form a shaftseal part. Also in the use manner, in the same manner as that describedin use example 3, penetration leak prevention and high sealingproperties between the stuffing box 10 and the valve rod or the like 11can be maintained.

USE EXAMPLE 5

In place of the gland packings G7 and G9 or G10 used in use example 3shown in FIG. 20, the gland packing G16 of embodiment 16 and the glandpacking G18 of embodiment 18 are similarly used so as to form a shaftseal part. Also in the use manner, in the same manner as that describedin use examples 3 and 4, penetration leak prevention and high sealingproperties between the stuffing box 10 and the valve rod or the like 11can be maintained.

FIG. 23 is a table showing stress generating states in the case wherethe gland packing G1 of the first embodiment and the gland packing G6 ofthe sixth embodiment are used as the gland packing of the invention, agland packing G01 consisting only of the die mold packing 51 shown inFIG. 25 is used as a prior art packing, gland packings G02 and G03 areused as comparison packings, the gland packing G02 being formed bybringing ring-like seal members 60 and 60 into tight contact with thewhole area of the both end faces in the axial direction of the die moldpacking 51 as shown in FIG. 30, the gland packing G03 being formed byintegrally projecting ring-like projected parts 61 and 62 from the bothend faces in the axial direction of the die mold packing 51 and in theouter and inner end portions in a radial direction, and bringingring-like seal members 63 and 63 of a thickness corresponding to thesame height as that of the projected parts 61 and 62 into tight contactwith the both end faces in the axial direction of the die mold packing51 excluding the projected parts 61 and 62, and a constant compressionforce f is applied in the axial direction to the gland packings. In thefigure, the length of each arrow corresponds to the magnitude of thestress.

As seen from FIG. 23, according to the gland packings G1 and G6 of thefirst and sixth embodiments of the invention, the stresses of theportions corresponding to the ring-like projected parts 2 and 3, and 6and 7 are very greater than those in the prior art packing and thecomparison packings, the performance of preventing a fluid from leakingthrough the ring-like projected parts 2 and 3, and 6 and 7 is excellent,and the tight adhesion force against the stuffing box and the outerperipheral face of a valve rod or the like is large so as to exhibitexcellent sealing properties.

FIG. 24 is a table showing results of gas-seal tests which wereconducted on use examples 1 to 5 of the gland packing of the invention,and the use examples of prior art packings shown in FIGS. 27 and 29under the conditions that nitrogen gas N2 was filled at 21 Kgf/cm2 atordinary temperature.

As seen from the figure, according to the gland packing of theinvention, the leakage amount is very small even in the case where thetightening face pressure is low, thereby exhibiting excellent sealingproperties. In a region to which a high tightening face pressure isapplied, the leakage amount can be improved to a level of 1/10 to 1/100.

INDUSTRIAL APPLICABILITY

According to the invention, even when a pressurized fluid penetratesinto minute gaps formed in windingly laminated parts of an expandedgraphite tape constituting the die mold packing part, it is possible toprevent the fluid from leaking, and also to suppress stress relaxationdue to the swelling out in an axial direction of the die mold packingpart. When the gland packing is to be used while being charged in astuffing box, furthermore, the projected part which is formed on the diemold packing part so as to be outward projected in the axial directioncan be easily deformed only by applying a low tightening force in theaxial direction, and hence the density of the projected part isincreased and a large stress is generated in a radial direction so thatthe packing is strongly brought into tight contact with the inner faceof the stuffing box and the outer peripheral face of a valve rod or thelike. This surely prevents penetration leakage through the projectedpart from occurring, and the sealing properties between the stuffing boxand the valve rod can be maintained at a high level. Furthermore, thering-like projected part has a closely packed folded structure and isvery elastic, and hence the ring-like projected part can satisfactorilyfollow a small amount of wear, thereby attaining an effect that thepenetration leak prevention and high sealing properties can bemaintained for a long term.

According to the invention, when the gland packing is to be used whilebeing charged in a stuffing box, the ring-like projected part which isformed on the die mold packing part so as to be outward projected in anaxial direction, and the ring-like seal member are easily deformed onlyby applying a low tightening force in the axial direction, so that theprojected part and the seal member are positioned in a planesubstantially perpendicular to the axis of the valve rod or the like,and hence the density of the projected part is increased and a largestress is generated in a radial direction so that the projected part andthe seal member are strongly brought into tight contact with the innerface of the stuffing box and the outer peripheral face of the valve rodor the like. In the same manner as described above, therefore, thepenetration leak prevention and high sealing properties can bemaintained for a long term.

According to the invention a ring-like projected part and ring-like sealmember are strongly brought into tight contact with the inner face of astuffing box and the outer peripheral face of a valve rod or the like,only by applying a low tightening force in an axial direction, wherebythe penetration leak prevention and high sealing properties can beensured maintained for a long term.

1. A gland packing, comprising: a die mold packing part formed bywinding and die-molding a laminated expanded graphite tape, said formeddie mold packing part defining an axial direction, a pair of end faceswith one of the end faces being perpendicular to the axial direction andthe other of the end faces being angled with respect to the axialdirection, an inner end portion, an outer end portion, and acircumferential projected part which projects outwardly from at leastone of said end faces; and at least one ring-shaped seal member engagingone of said pair of end faces, wherein: said at least one ring-shapedseal member has an inner face, an outer face, an inner peripheralsurface and an outer peripheral surface, with said inner face in tightcontact with one of said pair of end faces in said axial direction ofsaid die mold packing part, said outer face of said at least onering-shaped seal member being an oblique circular cone face extendinginward at a constant slope in said axial direction when viewed in thedirection of said outer end portion from said inner end portion; andsaid circumferential projected part has a projection end face positionedin a plane which is an extension of said oblique circular cone face,said circumferential projected part further has, an inner peripheralsurface and an outer peripheral surface, with at least one of said innerperipheral surface and said outer peripheral surface of said projectedpart in tight contact with one of said inner peripheral surface and saidouter peripheral surface of said at least one ring-shaped seal member.2. The gland packing according to claim 1, wherein: said at least onering-shaped seal member is selected from a lamination of a sheetmaterial having impermeability, a single plate, and metal foil.